Arene oxides have been identified as primary intermediates in the microsomal metabolism of such aromatic compounds as benzene, naphthalene, and the carcinogenic 1, 2, 5, 6-dibenzanthracene. This coupled with the observation that K-region oxides of certain polynuclear hydrocarbons are capable of inducing "malignant transformation" of rodent cells, and in fact are more active than their respective parent aromatics in this regard, strengthens the contention that epoxides are in fact responsible for the carcinogenic activity of polynuclear hydrocarbons. We intend to evaluate several synthetic routes to these substrates and to employ readily available dicarboxylic acids as precursors. The methods envisioned offer flexibility in obtaining substituted arene oxides for evaluation as potential carcinogenic agents and comparison with their unsubstituted counterparts. The photochemistry of the photolabile arene oxides will also be investigated and photoproducts made available for screening. The results of the photochemical studies in this area may have significance in connection with the enhancement of aberrant effects on biological systems produced by polynuclear hydrocarbons upon exposure to light or in their detoxification processes. We have demonstrated that arene oxides undergo photorearrangement reactions and plan to investigate potential photoinduced nucleophilic additions which we feel may occur on the basis of previous experience with other aryloxiranes. The possibility also exists that K-region oxides may undergo a multistep or sequential conversion to M-region oxides by way of oxepin intermediates will be evaluated.